What does the term 'linkage' in genetics refer to?

The term 'linkage' in genetics specifically refers to the phenomenon where genes located on the same chromosome tend to be inherited together due to their proximity on that chromosome. When genes are physically close to each other, the chance of them being separated during the process of recombination (which occurs during meiosis) is reduced. This means that they are more likely to be passed on together as a unit to the next generation.

This is a fundamental concept in genetics because it helps explain why some traits are often inherited together, which can create patterns in inheritance that are not in line with Mendel's laws of independent assortment. For example, if two genes are linked, they may show a higher frequency of inheritance in combination than would be expected if they assorted independently.

Understanding gene linkage is crucial for mapping genes on chromosomes and for predicting inheritance patterns in genetic studies, which enhances our knowledge of genetic disorders and traits.